Guiding and controlling device for cowlings



Sept. 28, 1943. R. RAMSIHORNQ GUIDING AND CONTROLLING DEVICE FORCOWLINGS Filed March 27, 1940 UNITED STATES PATENT OFFICE GUIDING ANDCONTROLLING DEVICE FOR COWLINGS Reinhard Ramshorn, Munich, Grafelfing,Germany; vested in the Alien Property Custodian Application March 27,1940, Serial No. 326,140 In Germany April 1, 1939 5 Claims.

The invention relates to means for guiding and controlling the airentering the fairing or engine cowling of air-cooled internal combustionengines, particularly for aircraft, preferably radial engines.

An object of this invention is to provide an improved cowling which notonly has a favorable external aerodynamic shape, but also improves theguiding of cooling air within the cowling.

Another object of this invention is to provide an improved cowlinghaving reduced air resistance and which, at the same time, carriescooling air back to the engine without production of unfavorable anddisturbing eddies and vortices.

A further object of this invention is the provision of an engine cowlinghaving a section rotating with the propeller blades and constructed withan improved, adjustable cooling air inlet opening.

A more specific object of this invention is the provision of an enginecowling for aeroplanes, having a section rotatable with the propeller,and constructed with internal air-accelerating baffles for supplyingcooling air to the engine.

These and other features of the invention will be best understood andappreciated from the following description of a preferred embodimentthereof described for purposes of illustration and shown in theaccompanying drawing, in which:

The single figure is a longitudinal view, partially in cross-section, ofthe forward part of an engine cowling in accordance with the presentinvention.

The engine cowling arranged symmetrically with respect to thelongitudinal axis I of the engine (not shown), includes a stationarycowling part 2 surrounding the cylinders and the part 4 rotating withthe propeller blades 3. A cylindrical wall 5 is mounted co-axiallywithin the part 4. A cap 6, capable of being displaced in the directionof axis I for controlling the inlet cross-sectional area of the annularconduit I defined by the cowling part 4 and the wall 5, is slidablymounted on the said wall 5. The baflles B and the supporting blades Isurrounding the blade butt ends 9 serve at the same time to interconnectand mutually support the walls 4 and of the annular conduit I. Thebafiles 8 and the blades ID are preferably arranged obliquely to thelongitudinal axis I in such a manner that they also serve as blowers,thus effecting an acceleration of the air entering the cowling 4 andpermitting a reduction of the power to be delivered to the fan II. Thefan II, of course, can also be omitted.

In this manner, according to the invention all parts are of low airresistance and of suitable construction, and the blade butt ends 9,wellfaired, revolve in a directed air current, so that a far-reachingreduction of the profile drag and thus a remarkable increase inefficiency is obtained, which results in an increase of speed of thevehicle in question. In this respect, further, it has provedadvantageous if the stationary part 2 of the cowling somewhat overlapsthe part 4 in order that the pressure still existing in the boundarylayer as far as possible compensate the interior pressure, and noformation of vortices or thickening of the boundary layer by theescaping air occurs at the point I2.

Although no means have been illustrated effecting movement of the cap 6for adjusting the cross-sectional area of the air inlet, it will beobvious to those skilled in this art that this adjustment may beeffected manually by means of suitable linkages or the like, or, usingwell-known apparatus, automatically by a suitable regulator responsiveto engine temperature or, if desired, in accordance with chargingpressure. The particular means for bringing about adjustment of the cap6 does not, however, form part of the present invention, and accordinglywill not be described or illustrated in detail.

Having described an illustrative embodiment of the invention, it ispointed out that various changes and modifications therein may be madewithout departing from the invention, it being intended that the patentshall cover, by suitable expression in the appended claims, all featuresof patentable novelty existing in the invention disclosed, asillustrated by the embodiment described.

Iclaim:

1. In a cowling for engine-driven aircraft, the combination of a firststationary cowling section adapted to surround the engine proper, apropeller adapted to be driven by the engine, and a second cowlingsection rotatable with said propeller and positioned forwardly of saidfirst cowling section, said second cowling section including astream-lined outer wall open at both ends, surrounding and extendingforwardly of the propeller butt ends, an inner cylindrical wall coaxialwith and spaced from said outer wall to form an annular air-guidingspace between the two walls, and baffles in said annular spaceinterconnecting the two walls, said baiiles being so shaped as to assistin directing the oncoming air rearwardly through said annular space tosaid engine.

2. The combination according to claim 1, in

- which said baffles comprise suitably shaped plates covering thatportion of the propeller butt ends in the annular space between saidwalls.

3. The combination according to claim 1, in which said baifies areshaped as air-accelerating blades.

4. The combination according to claim 1, in combination with bafflingair-guiding blades surrounding that portion of the propeller butt ends10 in the annular space between said walls, said baflles and saidair-guiding blades being shaped as air-accelerating blades.

5. The combination according to claim 1, in combination with astream-lined cap slidably adjustable upon and closing the forward end ofsaid inner cylindrical wall for varying the cross-sectional area of theair inlet opening formed at the forward end of the two walls.

REINHARD RAMSHORN.

